Toshishita Kareshi No Renai KanrihekiA Sadist Devoted to You; Los Deseos Obsesivos De Mi Chico (Spanish); Mes Habitudes avec mon petit ami (French); Young Boyfriend's Love Management Habit; 君に捧ぐサディスティック; 年下彼氏の恋愛管理癖; 年下彼氏的戀愛管理癖

Satoshi is a fragile research student who immerses himself so much in his research, that he often forgets to eat and sleep. He has a pet-master relationship with Izumi, his junior at the same lab, a relation which they themselves and people around them are aware of. Izumi is supposed to limit himself in taking care of Satoshi, but after he learns that he was attacked by a man, his feelings towards Satoshi started to change. These feelings are possessiveness and a desire to monopolize or...?